Detecting means for yarn processing apparatus

ABSTRACT

Apparatus for processing yarn comprising a disc and roller supported at opposite sides of the plane of a pair of running yarns for frictional engagement with the yarns, with the roller rotating in a direction opposite to the direction of movement of the yarns and with the disc free to turn about an axis at its center perpendicular to the plane of the yarns and midway between the yarns so that the disc is adapted to be maintained in a condition of balanced equilibrium by uninterrupted movement of the yarns between the surfaces of the disc and the roller, and to stop the apparatus in the event that it becomes unbalanced.

United States Patent 1 1 1111 3,794,252

Abbott 1451 Feb. 26, 1974 15 DETECTING MEANS FOR YARN 363,274 8/1962 Switzerland 242/38 PROCESSING APPARATUS 45,400 l/1962 Poland 242/42 [75] Inventor: Samuel L. Abbott, Wilton, NH. E S l N G I h Primary xaminertan ey i reat [73] Asslgnee: Abbott Machme Attorney, Agent, or Firm Dike, Bronstein, Roberts &

Cushman [22] Filed: June 25, 1971 52 us. Cl. 242/38 242/42 Apparatus Processing Yam mPYi5ing a disc and 511 Int. Cl B65Th 63/02 SUPPed at Sides Of the Plane a [58] Field of Search"; 242/38 40 42 28/64 of running yarns for frictional engagement with the yarns, with the roller rotating in a direction opposite 56] References Cited go the direction of increment of tthe yarns and with dthe A 180 tee to turn a on an axis at its center perpen 1C- UNITED STATES PATENTS ular to the plane of the yarns and midway between the 1,608,362 1 H1926 Bootes 242/38 yams so that the disc is ada ted to be maintained in a l 995 730 3 1935 Abb 242 38 p 2'093628 9x937 242/38 condition of balanced equilibrium by uninterrupted 274059l 4/1956 2; 242438 movement of the yarns between the surfaces of the 344l23l 4/1969 Si'egel 242,38 disc and the roller, and to stop the apparatus in the r event that it becomes unbalance d FOREIGN PATENTS OR APPLICATIONS 1,267,655 6/1961 France 242/38 17 Claims, 11 Drawing Figures l4 I 24 I l as .68

A 2 32 3o 2. "26d 2 w- PATENIEB FEBZS I974 v sum 1' BF 3 DETECTING MEANS FOR YARN PROCESSING APPARATUS BACKGROUND OF THE INVENTION the number of running yarns; .which functions in addition to a stop motion as tensioning means, as means for equalizing tension in running yarns, as a detector of broken and/or long large defects and in particular for use in conjunction with yarn doubling and twisting apparatus. Additionally, the device is designed to detect an interruption in a running yarn. and to stop the machine quickly enough to leave the broken end free for knottingwithout resort to finding operations.

SUMMARY As herein illustrated, the invention comprises in a yarn processing apparatus of the kind wherein two yarns are travelling in the same direction next to each other and means for effecting such movement of the yarn, friction engendering means through which the two yarns travel, said friction engendering means being maintained in a predetermined condition of balanced equilibrium by uninterrupted travel of the yarns therethrough and means operable by imbalance of said friction engendering means for disabling said first means. The friction engendering means is supported for angular movement about an axis perpendicular to a plane containing the yarns and there is means supporting the running yarns in engagement with the friction engendering means symmetrically with respect to said axis such that uninterrupted movement of the yarns travelling in engagement with said friction engendering means maintains it in stable equilibrium. More specifically, the friction engendering means embodies flat surfaces of equal linear extent with which the running yarns are held engaged, said surfaces being located symmetrically with respect to said axis of angular movement so that equal frictional forces applied to the symmetrically situated surfaces will maintain the device in balanced equilibrium. Such surfaces may comprise the flat surface of a disc mounted for free rotation about an axis perpendicular to a plane containing the.

yarns and situated midway therebetween or may comprise two parts mounted for rotation about a common axis perpendicular to a place containing the yarns, the surfaces being of equal linear extent and equally distant from said axis, or optionally two cylindrical surfaces rotatable about a common axis and supported for rotation about an axis perpendicular to a plane containing the yarns. The means for supporting the yarns engaged with the friction engendering means comprises a part adapted to move in a direction opposite to the direction of movement of the yarns but to have substantial tangential engagement with the friction engendering means at the place of engagement of the yarns therewithpSaid part is in the form of a roller supported for rotation about an axis spaced from and parallel to the plane of the yarns with its surface tangent to the plane of the yarns and optionally may comprise axially spaced peripheral surfaces situated at the approximate spacing of the two running yarns and having a clearance space therebetween. Uninterrupted movement of the yarns through the friction engendering means so a long as the yarns run uninterruptedly therethrough maintains the device in a condition of balanced equilibrium. A break in one yarn or a large defect by upsetting the balance is operative to cause the device to break the other yarns and/or to stop the machine.

The invention will now'be described in greater detail with reference to the accompanying drawings wherein:

FIG. 1 is an elevation of a portion of a doubling machine in which to yarns-are unwound from packages combined and wound onto a single package and showing the device of this invention between the packages;

FIG.2 is an elevation, to much larger scale, taken on the line 2-2 of FIG. 1;

FIG. 3 is an elevation from the right side of FIG. 2 partly in section;

FIG. 4 is an elevation of the support for the friction engendering disc broken away in part;

FIG. 5 is an elevation of an alternative form of friction engendering means;

FIG. 6 is an elevation of another form of friction engendering means;

FIG. 7 is an elevation of still another form of friction engendering means;

FIG. 8 diagrammatically illustrates an optical control;

FIG. 9 shows a fragmentary part of the device pro vided for the control shown in FIG. 8;

FIG. 10 diagrammatically illustrates a pneumatic control; and v FIG. shows a fragmentary part of the device provided for the control shown in FIG. 10.

machine, to the drawings, the device of this invention is illustrated in conjunction with a single or multiple winding machne, a single winding unit being disclosed in FIG. l. The unit comprises a cone-l0 supported at its larger end by a bracket member 12 with its surface parallel to a driven roll 14, the supporting arm for the cone being mounted for movement from an upright position to a position of parallelismwith the drive shaft. Below the cone there are mounted on the unit laterally spaced cones 20-20 from which yarns are drawn for combining and winding onto the cone 1.0.

The device of this invention is mountedon the supporting structure between thecone l0 and the cones 20-20 in a position to intercept the yarns yy before they are brought together for winding onto the cone 10. For the purpose of guiding the yarns to the device the support is provided with spaced yarn guides 22-22 and for the purpose of bringing the yarns together there is provided a single yarn guide 24. One component of the devicecomprises'a shaft 26 mounted in transversely spaced bearings 2828 projecting forwardly from the support with its axis at right angles to the direction of travel of the yarns from the guides 22-22 to the guide 24. The shaft 26 axially spaced, peripheral surfaces 30-30 which are substantially tangent to the plane of the running yarns and which are so axially spaced that yarns run in tangential'engagement with these surfaces intermediate the opposite axial extremities. Between the cylindrical portions 30-30 there is a cylindrical portion 32 of small diameter.

The other component of the device comprises a disc 34 having a flat circular surface 36 (FIG. 3) mounted in confronting relation to the shaft 26 in tangential relation to the surfaces 30-30 and perpendicular to the plane of the yarns. The disc 36 contains a central aperture 38 (FIG. 4) by means of which it is rotatable mounted on a spindle 40 fixed to the upper end of an arm 42, the lower end of which has a part 44 pivotally supported at 40 on which there is an adjustable weight W by means of which the pressure between the disc 34 and the cylindrical surfaces 30 30 may be increased or decreased.

The disc 34 has on its rear surface a hub 48 which is turned down to provide an external conical cam 50 and the spindle 40 has on it a hub 52 internally recessed to provide a conical cam 54 corresponding in configuration to the cam 50.

A bracket 56 (FIG. 3) is secured to the support so as to extend horizontally forwardly therefrom beneath the disc 34 beyond the arm 42 and has on it a post 58, at the upper end of which there is an internally threaded boss 60. A screw 62 is threaded into the boss 60 so that its inner end is adjacent the arm 42 and by rotating the screw 62 the disc 34 may be moved to a predetermined position with respect to the surfaces of the cylindrical members 3030. A lock nut 64 is mounted on the screw to lock the screw in an adjusted position.

An apron 66 is also mounted on the boss 60 which extends rearwardly therefrom above the disc 34 and has spaced parallel edges 68-68 adapted to guide and hold the yarns y-y in substantially spaced parallel relation as they travel from the-eyes 2222 between the cylindrical portions 3030 and the disc 34, and which allows the yarns then to come together at the eye 24 and thus to travel together to a traversing element by means of which they are wound onto the cone 10.

The winding apparatus as herein illustrated is of conventional construction and the supporting arm 70 for the cone is mounted for rotation about a horizontal axis to permit elevation of the cone relative to the driven roll 14 so that it may be removed when filled. The movement of the arm 70 to the position wherein the surface of the cone is parallel to the driven roll 14 operates to frictionally effect rotation of the shaft 26 in the direction of the arrows shown in FIGS. 1 and 2, so that the surfaces 30-30 at their place of tangency with the disc 34 are travelling in directions opposite to the movement of the yarns yy.

So long as the yarns y-y travel in an uninterrupted fashion between the surfaces 3030 and the disc 34, providing that the yarns are of the same size and material, the frictional resistance to movement of the yarns imposed by the pressure of the disc 34 against the surfaces 3030 will produce the same amount of friction and this will maintain the disc 34 in a condition of stable equilibrium since the reaction to the frictional force at one side will balance the reaction of the frictional force on the other side. Actually the inherent small variations in the yarns will impart successive, very slight unbalancing impulses in each direction but of not sufficient magnitude to upset the continued running of the yarn between the surfaces. lf, however, one of the yarns breaks, the contact of the rotating surface 30 with the surface of the disc at the side where the yarn breaks will tend to rotate the disc in a downward direction at that side thus upsetting the equilibrium. Rotation of the disc 34 from its balanced position will cause the cam 50 to ride out of the cam 54 thus moving the disc forwardly on its spindle .40 toward the axis of the shaft 26. Such forward movement increases the friction of the disc on the unbroken yarn and if the disc has been adjusted to provide for the purpose, such friction will break the other yarn. The operation takes place very rapidly so that the second yarn becomes broken before the end of the first yarn is wound onto the package. Simultaneously with this it is desirable to stop the machine so that the broken ends may be retrieved and retied and so means is provided with is operable by the unbalance of the disc 34 to stop the machine. Such means may be in the form ofa mechanical, electrical, optical or pneumatic means responsive to rotation of the disc 34 beyond a predetermined amount. Following a break the ends of the yarns are again tied and the yarns are guided between the disc and surfaces 30-30 substantially automatically and very gently without substantial danger of rebreaking the yarns by means of conical surfaces 7272, provided for this purpose, disposed axially outwardly of each of the cylindrical surfaces 3030.

The device operates not only to stop the apparatus when a yarn breaks but may also be adjusted to stop the machine when a long large defect occurs and so functions as a slub catcher. When such a defect passes between the disc and one of the surfaces 30 it increases the frictional resistance therebetween, causing unbalance of the disc 34 so that the disc rotates and is forced toward the surface with increasing pressure and breaks the yarn whereupon the disc immediately becomes unbalanced in the opposite direction to break the other yarn thus stopping the machine. The slub may now be removed and the ends tied up so that the operation may be continued.

The device also provides for applying a predetermined amount of friction to the running yarn and so long as the friction is maintained constant in the two yarns the device will permit the yarns to run through it and to be wound onto the package at a uniform tension. If the friction in one yarn increases for some reason the device will become unbalanced and break the yarn thus stopping the machine and compelling the operator to make readjustments.

As was previously mentioned it is ordinarily necessary to use a stop motion, slub catcher or tension device for each running yarn. ln constrast the device shown herein enables reducing the number of such devices to half that normally required.

The combination of the cylindrical surfaces 3030 and the disc 34 collectively constitute friction engendering means through which running yarns are permitted to pass freely so long as such passage is uninterrupted and which through imbalance will operate to stop the machine. Such friction engendering means may take other forms as, for example, as shown in F108. 5, 6 and 7. The same shaft 26 is employed with each of these modified forms and is shown therein with the same reference character 26 applied thereto. In FIG. 5 in place of the disc 34 there are two flat plates 7474 rigidly connected to the opposite ends of a bar 76, the latter containing. midway between its ends a bearing 78 which is adapted to be rotatably mounted on the spindle 40 on which the disc 34 was mounted. With this construction as long as the yarns y-y run at the same speed the plates 7474 will balance each other but should the frictional resistance to running of one yarn change from that of the other by reason of breaking the presence of a slub or change in size or kind of the yarn the plastes will become unbalanced and this unbalance may be'employed through mechanical, electrical, optical or pneumatic means to stop the machine. As with the disc the cam members 50 and 54 would force the plates 74-74 against the surfaces 30-30 to brek the yarn.

FIG. 6 shows a structure similar to FIG. 5 except that the plates 74-74 are pivotally mounted at 80-80 at the ends of the bar 76 so that they can rotate freely and will not interfere with or apply any lateral forces to the running yarn.

FIG. 7 shows a modification in which the bar 76 has rotatably mounted on it two rollers 82-82 with their surfaces tangent to the surfaces 3030 of the shaft 26. These rollers are free to turn on the bar 76 and will ordinarilybe driven in a counterclockwise direction by the running yarns. A break in one ofthe yarns will bring the roller 82 at that side into engagement with the surface 30 and cause rotation of the roll 82 in a clockwise direction thus unbalancing the structure causing it to turn rapidly and such unbalancing is again used to effect operation of mechanical or electrical means to stop the apparatus.

The drive for the shaft 26 is shown herein diagrammatically by the dot and'dash line 26a since frictional drives of the kind employed herein for such purposes are well known in the art. As related above, mechanical, electrical, optical or pneumatic means may be provided for stopping the machine when the disc becomes unbalanced. Specifically, for example, as shown in FIG. 8 a beam of light from a photocell 84.may be directed onto a white area 86 applied to the disc which reflects the beam back to the photocell and so long as the disc remains in equilibrium maintains the power supply to the drive motor M for the apparatus but when the disc moves out of balance the white area is removed from the beam and the latter is not reflected back with the result that the power circuit'is disabled.

FIG. 10 shows an alternative in the form ofa pressure switch 88 through which a stream of air is directed against the disc and so long as the disc remains in balance the resistance to the stream of air holds the switch in an inoperative position. Arcuate apertures 90-90 may be provided at each side of the center balanced position of the disc so that when the disc roatates out of its balanced position the air stream passes through the apertures thus actuating the switch and disabling the power to the drive motor. The photocell or air switch as the case may be operates to break the circuit to the motor M. Other types of device for the foregoing purpose may be employed.

If desired it is within the scope of the invention to provide signal lights which will become illuminated by unbalance of-the disc to visually call attention of the unbalanced condition of the apparatus to the operator.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents falling within the scope of the appended claims.

l claim:

l. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement of the yarns, friction engendering means through which the two yarns travel, said friction engendering means comprisinga disc having a flat surface against which the yarns are held, means mounting the disc for rotation about an axis perpendicular to a plane containing said yarns and situated midway between. so that said yarns run over areas of said disc of corresponding length which are equidistant from the center of the disc, said disc being free to turn about said axis and being maintained in a condition of balanced equilibrium by uninterrupted travel of said running yarns, and, means operable by failure of said disc to be maintained in said condition of balanced equilibrium to disable said first means.

2. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement of the yarns, friction engendering means through which the two yarns travel, said friction engendering means comprising parts hving flat surfaces over which the yarns are adapted to travel, means supporting the parts for turning about a common axis perpendicular to a plane containing the yarn, said surfaces being of equal linear extent and equidistant from said axis, and each being rotatable about an axis parallel to said common axis and equally distant therefrom, said parts being adapted to be maintained in a condition of balanced equilibrium by uninterrupted movement of said running yarns over said surfaces, and means operable by failure of said parts to be maintained in said condition of balanced equilibrium 'to disable said first means.

3. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the two yarns travel, 1

said friction engendering means comprising confronting parts, means for effecting movement of one of the parts in a direction opposite to the direction of movement of the yarns means supporting the other of the parts so as to be free to rotate about an axis located midway between the courses of the two yarns and perpendicular to a plane containing said yarns, said other part being adapted to be held in stable equilibrium by uninterrupted travel of the yarns between said parts, and said one part being operable by an interruption in one of the yarns to apply an unbalancing force to the other part, and means operable by said imbalance of said other part to increase the resistance to running of the other yarn.

4. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering meanscomprising confronting parts, means for effecting movement of one of the parts in a direction opposite to the direction of movement of the yarns, means supporting the other of the parts so that it is free to rotate about an axis located midway between the courses of the two yarns and perpendicuuar to a plane containing said yarns, said other partbeing adapted to be held in stable equilibrium by uninterrupted travel of the yarns between said parts, said one part being operable by an'interruption in one of the yarns to apply an unbalancing force to the other part, and means operable by said unbalancing of said other part to cause the latter part to break said other yarn.

5. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the two yarns travel, said friction engendering means comprising confronting parts, means for effecting movement of one of the parts in a direction opposite to the direction of movement of the yarns, means supporting the other of the parts so as to be free to rotate about an axis located midway between the courses of the yarns and perpendicular to a plane containing said yarns, said other part being adapted to be held in stable equilibrium by an uninterrupted travel of the yarns between said parts, and said one part being operable by a break in one of the yarns to apply an unbalanced force to the other part, and means operable by said unbalancing of said other part to increase the resistance to running of said other run to the point of breaking said other yarn.

6. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a roller supported for rotation about an axis parallel to the plane containing the yarns with its surface tangent thereto and a disc supported in confronting relation to the roller for free rotation about its center on an axis perpendicular to the plane of the yarns, means rotating the roller in a direction such that its surface at the place of tangency travels in a direction opposite to the movement of the yarns, said disc being adapted to be held in a condition of balanced equilibirum by uninterrupted movement of the yarns and to become unbalanced by a break in one of the yarns, said roller operating in the absence of a yarn between it and the disc to increase said imbalance, and means operable by said imbalance to disable the first means.

7. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there 'is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a roller supported for rotation about an axis parallel to the plane containing the yarns with its surface tangent thereto and a disc supported in confronting relation to the roller for free rotation about is center on an axis perpendicular to the plane of the yarns, means rotating the roller in a direction such that its surface at the place of tangency travels in a direction opposite to the movement of the yarns, said disc being adapted to be held in a state of balanced equilibrium by uninterrupted movement of the yarns and to be imbalanced by a break in one ofthe yarns, and means operable by said imbalance to increase the frictional resistance to running of the other yarn between the disc and roller to an extent to break said yarn.

8. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a roller supported for rotation about an axis parallel to the plane containing the yarns with its surface tangent thereo, a disc, means supporting the disc in confronting relation to the roller with its center located on the line of tangency of the disc and roller for rotation about an axis at said center and perpendicular to said plane, means for effecting rotation of the roller in a direction such that at the place of tangency its surface is travelling in a direction opposite to the movement of the yarns, said '8 support supporting the disc in substantially balanced equilibrium so long as the yarns travel uninterruptedly between the disc and roller, and mens operable by imbalance of the disc in either direction of rotation about said perpendicular axis to force the disc toward said roller.

9. A yarn processing apparatus wherein we yarns are travelling in the same direction next to each other and there is means for effecting such movement. friction engendering means through which two yarns travel, said friction engendering means comprising a roller supported to rotate about an axis parallel to the plane containing the yarns with its surface tangent thereto, a disc, means supporting the disc in confronting relation to said roller with its center on the line of tangency of the disc and roller for rotation about an axis at said center and perpendicular to said plane, means for effecting rotation of the roller in a direction such that at the place of tangency its surface is travelling in a direction opposite to the movement of the yarns, said support for the disc comprising a spindle about which the disc rotates, and means for effecting movement of the disc toward the roller comprising mutually engaged cams on the disc and spindle respectively which support the disc in a predetermined position of balanced equilibrium so long as the yarns travel uninterruptedly therebetween,

said cams being operable by imbalance of said disc relative to the roller to force the disc toward the roller.

10. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a roller supported for rotation about an axis parallel to the plane containing the yarns with its surface tangent,

thereto, a disc, means supporting the disc in confronting relation to the roller with its center on the line of tangency of the disc and roller comprising a spindle on which the disc is rotatably mounted, an arm pivotally supporting the spindle for substantially rectilinear movement toward the roller, means urging said arm in a direction to hold the disc engaged with the yarns running between the disc and the roller, and cam means on the disc and spindle operable by rotation of the disc about the axis of the spindle to press the disc against the travelling yarns.

11. Apparatus according to claim 10, comprising an adjustablepart bearing onthe arm operable to hold the disc at a predetermined distance from the surfaces of the roller.

12. in a yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a rotating member embodying axially spaced cylindrical surfaces with which the yarns areengaged, said member being adapted to rotate in a direction such that said cylindrical surfaces at their place of tangency with the yarns are moving in a direction opposite to that of the yarns, a disc, means supporting the disc in confronting relation with the rotating member with its center situated midway between the cylindrical surfaces for rotation about an axis perpendicular to its surface, said disc having a diameter at least as great as the distance between the cylindrical surfaces and being free to rotate on its axis, and means yieldably holding the disc aginst the yarns running between it and said cylindrical surfaces.

13. Apparatus according to claim 12, wherein the portion of the rotating member intermediate the axially spaced cylindrical surfaces is of smaller diameter than said cylindrical surface, providing therebetwecn a clearance space.

14. Apparatus according to claim 12, wherein there are portions of the roller at tue outer ends of the axially spaced cylindrical surfaces which taper from diameters small than the diameter of the cylindrical portions to diameters corresponding to the diameters of the cylindrical portions.

15. Apparatus according to claim 12, comprising spaced guide eyes preceding the'friction engendering means in the direction of movement of the yarns through which the yarns are guided in predetermined spaced relation for movement toward said friction engendering means and a device having spaced parallel edges supported in a position such that said edges are engaged by the running yarns after they travel through said friction engendering means for maintaining the yarns in spaced parallel relation during such travel.

16. Apparatus according to claim 15, comprising a single. guide eye beyond the friction engendering means for bringing the yarns together.

17. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement of the yarns, friction engendering means through which the two yarns travel. said friction engendering means comprising parts between which the running yarns are frictionally held, means mounting one of the parts for angular movement about an axis perpendicular to the plane containing said yarns and situated midway between so that said running yarns travel over portions of the part of corresponding dimensions in the direction of travel of the yarns which are equidistant from said axis, said one part being free to turn about said axis and and being maintained in a condition of balanced equilibrium by uninterrupted travel of said running yarns, and means operable by failure of said one part to be maintained in said condition of balanced equilibrium to 

1. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement of the yarns, friction engendering means through which the two yarns travel, said friction engendering means comprising a disc having a flat surface against which the yarns are held, means mounting the disc for rotation about an axis perpendicular to a plane containing said yarns and situated midway between, so that said yarns run over areas of said disc of corresponding length which are equidistant from the center of the disc, said disc being free to turn about said axis and being maintained in a condition of balanced equilibrium by uninterrupted travel of said running yarns, and means operable by failure of said disc to be maintained in said condition of balanced equilibrium to disable said first means.
 2. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement of the yarns, friction engendering means through which the two yarns travel, said friction engendering means comprising parts hving flat surfaces over which the yarns are adapted to travel, means supporting the parts for turning about a common axis perpendicular to a plane containing the yarn, said surfaces being of equal linear extent and equidistant from said axis, and each being rotatable about an axis parallel to said common axis and equally distant therefrom, said parts being adapted to be maintained in a condition of balanced equilibrium by uninterrupted movement of said running yarns over said surfaces, and means operable by failure of said parts to be maintained in said condition of balanced equilibrium to disable said first means.
 3. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for Effecting such movement, friction engendering means through which the two yarns travel, said friction engendering means comprising confronting parts, means for effecting movement of one of the parts in a direction opposite to the direction of movement of the yarns , means supporting the other of the parts so as to be free to rotate about an axis located midway between the courses of the two yarns and perpendicular to a plane containing said yarns, said other part being adapted to be held in stable equilibrium by uninterrupted travel of the yarns between said parts, and said one part being operable by an interruption in one of the yarns to apply an unbalancing force to the other part, and means operable by said imbalance of said other part to increase the resistance to running of the other yarn.
 4. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising confronting parts, means for effecting movement of one of the parts in a direction opposite to the direction of movement of the yarns, means supporting the other of the parts so that it is free to rotate about an axis located midway between the courses of the two yarns and perpendicuuar to a plane containing said yarns, said other part being adapted to be held in stable equilibrium by uninterrupted travel of the yarns between said parts, said one part being operable by an interruption in one of the yarns to apply an unbalancing force to the other part, and means operable by said unbalancing of said other part to cause the latter part to break said other yarn.
 5. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the two yarns travel, said friction engendering means comprising confronting parts, means for effecting movement of one of the parts in a direction opposite to the direction of movement of the yarns, means supporting the other of the parts so as to be free to rotate about an axis located midway between the courses of the yarns and perpendicular to a plane containing said yarns, said other part being adapted to be held in stable equilibrium by an uninterrupted travel of the yarns between said parts, and said one part being operable by a break in one of the yarns to apply an unbalanced force to the other part, and means operable by said unbalancing of said other part to increase the resistance to running of said other run to the point of breaking said other yarn.
 6. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a roller supported for rotation about an axis parallel to the plane containing the yarns with its surface tangent thereto and a disc supported in confronting relation to the roller for free rotation about its center on an axis perpendicular to the plane of the yarns, means rotating the roller in a direction such that its surface at the place of tangency travels in a direction opposite to the movement of the yarns, said disc being adapted to be held in a condition of balanced equilibirum by uninterrupted movement of the yarns and to become unbalanced by a break in one of the yarns, said roller operating in the absence of a yarn between it and the disc to increase said imbalance, and means operable by said imbalance to disable the first means.
 7. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a roller supported for rotation about an axis parallel to the plane containing tHe yarns with its surface tangent thereto and a disc supported in confronting relation to the roller for free rotation about is center on an axis perpendicular to the plane of the yarns, means rotating the roller in a direction such that its surface at the place of tangency travels in a direction opposite to the movement of the yarns, said disc being adapted to be held in a state of balanced equilibrium by uninterrupted movement of the yarns and to be unbalanced by a break in one of the yarns, and means operable by said imbalance to increase the frictional resistance to running of the other yarn between the disc and roller to an extent to break said yarn.
 8. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a roller supported for rotation about an axis parallel to the plane containing the yarns with its surface tangent thereo, a disc, means supporting the disc in confronting relation to the roller with its center located on the line of tangency of the disc and roller for rotation about an axis at said center and perpendicular to said plane, means for effecting rotation of the roller in a direction such that at the place of tangency its surface is travelling in a direction opposite to the movement of the yarns, said support supporting the disc in substantially balanced equilibrium so long as the yarns travel uninterruptedly between the disc and roller, and mens operable by imbalance of the disc in either direction of rotation about said perpendicular axis to force the disc toward said roller.
 9. A yarn processing apparatus wherein wo yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which two yarns travel, said friction engendering means comprising a roller supported to rotate about an axis parallel to the plane containing the yarns with its surface tangent thereto, a disc, means supporting the disc in confronting relation to said roller with its center on the line of tangency of the disc and roller for rotation about an axis at said center and perpendicular to said plane, means for effecting rotation of the roller in a direction such that at the place of tangency its surface is travelling in a direction opposite to the movement of the yarns, said support for the disc comprising a spindle about which the disc rotates, and means for effecting movement of the disc toward the roller comprising mutually engaged cams on the disc and spindle respectively which support the disc in a predetermined position of balanced equilibrium so long as the yarns travel uninterruptedly therebetween, said cams being operable by imbalance of said disc relative to the roller to force the disc toward the roller.
 10. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a roller supported for rotation about an axis parallel to the plane containing the yarns with its surface tangent thereto, a disc, means supporting the disc in confronting relation to the roller with its center on the line of tangency of the disc and roller comprising a spindle on which the disc is rotatably mounted, an arm pivotally supporting the spindle for substantially rectilinear movement toward the roller, means urging said arm in a direction to hold the disc engaged with the yarns running between the disc and the roller, and cam means on the disc and spindle operable by rotation of the disc about the axis of the spindle to press the disc against the travelling yarns.
 11. Apparatus according to claim 10, comprising an adjustable part bearing on the arm operable to hold the disc at a predetermined distance from the surfaces of the rOller.
 12. In a yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement, friction engendering means through which the yarns travel, said friction engendering means comprising a rotating member embodying axially spaced cylindrical surfaces with which the yarns are engaged, said member being adapted to rotate in a direction such that said cylindrical surfaces at their place of tangency with the yarns are moving in a direction opposite to that of the yarns, a disc, means supporting the disc in confronting relation with the rotating member with its center situated midway between the cylindrical surfaces for rotation about an axis perpendicular to its surface, said disc having a diameter at least as great as the distance between the cylindrical surfaces and being free to rotate on its axis, and means yieldably holding the disc aginst the yarns running between it and said cylindrical surfaces.
 13. Apparatus according to claim 12, wherein the portion of the rotating member intermediate the axially spaced cylindrical surfaces is of smaller diameter than said cylindrical surface, providing therebetween a clearance space.
 14. Apparatus according to claim 12, wherein there are portions of the roller at tue outer ends of the axially spaced cylindrical surfaces which taper from diameters small than the diameter of the cylindrical portions to diameters corresponding to the diameters of the cylindrical portions.
 15. Apparatus according to claim 12, comprising spaced guide eyes preceding the friction engendering means in the direction of movement of the yarns through which the yarns are guided in predetermined spaced relation for movement toward said friction engendering means and a device having spaced parallel edges supported in a position such that said edges are engaged by the running yarns after they travel through said friction engendering means for maintaining the yarns in spaced parallel relation during such travel.
 16. Apparatus according to claim 15, comprising a single. guide eye beyond the friction engendering means for bringing the yarns together.
 17. A yarn processing apparatus wherein two yarns are travelling in the same direction next to each other and there is means for effecting such movement of the yarns, friction engendering means through which the two yarns travel, said friction engendering means comprising parts between which the running yarns are frictionally held, means mounting one of the parts for angular movement about an axis perpendicular to the plane containing said yarns and situated midway between so that said running yarns travel over portions of the part of corresponding dimensions in the direction of travel of the yarns which are equidistant from said axis, said one part being free to turn about said axis and and being maintained in a condition of balanced equilibrium by uninterrupted travel of said running yarns, and means operable by failure of said one part to be maintained in said condition of balanced equilibrium to disable said first means. 